1. Field of the Invention
This invention relates to a device for supplying a fluid such as a cutting fluid to the cutting portion of a tool such as a drill and the portion of a workpiece cut by the tool when the tool performs machining.
2. Description of the Prior Art
In a conventional fluid supply device of the kind described above, one example of which is disclosed in the specification of Japanese Utility Model Application Laid-Open (KOKAI) No. 61-184646, a tool holder for mounting and rotating a tool is formed to include a plurality of axially extending holes that supply a cutting fluid, a nozzle member is fitted into the distal end of each supply hole, the cutting fluid from a supply source of the same is fed under pressure to a nozzle, which is provided in each nozzle member, through the supply hole, and the cutting fluid is sprayed from these nozzles toward the cutting portion of the tool and the cut portion of the workpiece, thereby performing cooling and lubrication.
In another example of this conventional fluid supply device disclosed in the specification of Japanese Utility Model Application Laid-Open (KOKAI) No. 64-50034, a shank member to which the mounting shaft of a tool is fitted and secured is provided with a plurality of axially extending holes for supplying a cutting fluid, the distal end of each supply hole is formed to have an inclined nozzle hole connected thereto, the cutting fluid from a supply source of the same is fed under pressure to the nozzle holes through the supply holes, and the cutting fluid is supplied from these nozzle holes to the cutting portion of the tool and the cut portion of the workpiece.
In general, tools have cutting portions of a wide variety of shapes and dimensions, and machining conditions differ widely depending upon the shape of the workpiece, the depth to which the workpiece is machined, etc. Therefore, in order to supply a fluid such as a cutting fluid to the requisite portions accurately, it is required that the cutting-fluid supply holes, the nozzle members and the nozzle holes provided in the conventional tool holder or shank member described above be changed to conform to the tool used and the machining conditions. Consequently, machining and assembly are troublesome. An additional problem is that tool life is shortened unless the cutting fluid is supplied properly to such requisite locations as the base portion, mid-portion and distal end of the tool in conformity with the values of the length and outer diameter of the cutting portion of the tool. In particular, in a 24-hour operation that relies upon continuous unmanned machining, a long service life for a tool is strongly desired since a tool cannot be exchanged for a new one at night.